分解一句話【to which的疑惑】高分求解!
原句是：
Human facial expressions differ from those of animals in the degree to which they can be controlled on purpose.
在上面這句話里,to which的作用我不太清楚,很顯然,這是一個(gè)定語(yǔ)從句,其分解成兩句話便是：
1.Human facial expressions differ from those of animals in the degree.
2.Human facial expressions can be controlled on purpose.
很奇怪的是,上面兩句話中,沒(méi)有了to,這是怎么回事?to which在此句話中應(yīng)有的作用該是什么?請(qǐng)求賜教!謝謝!
另外,如果有朋友認(rèn)為我分解的不對(duì)的話,您也可以幫忙分解一下這句話.
非常感謝!